The world supplies of fossil oil are expected to be gradually exhausted in the following decades. This means that our main energy source for the last century will have to be replaced within a few decades, both to cover the present energy consumption and the coming increase in the global energy demand.
In addition, there are raised many concerns that the use of fossil energy is increasing the earth greenhouse effect to an extent that may turn dangerous. Thus the present consumption of fossil fuels should preferably be replaced by energy sources/carriers that are renewable and sustainable for our climate and environment.
One such energy source is solar light, which irradiates the earth with vastly more energy than the present and any foreseeable increase in human energy consumption. However, solar cell electricity has up to date been too expensive to be competitive with nuclear power, thermal power etc. This needs to change if the vast potential of the solar cell electricity is to be realised.
Most of the solar cells are produced from mono- or multi-crystalline silicon. Due to its high surface reflexivity, the surface of silicon based photovoltaic materials is usually surface treated to enhance the absorption of incoming radiation and thus increase the current generated in the cells. A rough surface improves the absorption while a flat surface reflects the incoming beam to a higher degree. In order to maximize the efficiency of the cells they are textured (roughened) and/or covered with an anti-reflection coating by depositing one or more dielectric layers.